Authors: Wanguang Zhang Qiongye Lei Zhengkui Li Huayang Han
Publish Date: 2015/10/06
Volume: 23, Issue: 3, Pages: 2677-2683
Abstract
Slightly polluted water has become one of the main sources of nitrogen contaminants in recent years for which constructed wetlands CW is a typical and efficient treatment However the knowledge about contribution of individual nitrogen removal pathways and nitrogen balance in constructed wetlands is still limited In this study a stableisotopeaddition experiment was performed in laboratoryscale constructed wetlands treating slightly polluted water to determine quantitative contribution of different pathways and temporal variation of nitrogen balance using Na15NO3 as tracer Microbial conversion and substrate retention were found to be the dominant pathways in nitrogen removal contributing 244–799 and 89–707 respectively while plant contributed only 46–111 through direct assimilation but promoted the efficiency of other pathways In addition microbial conversion became the major way to remove N whereas nitrogen retained in substrate at first was gradually released to be utilized by microbes and plants over time The findings indicated that N2 emission representing microbial conversion was not only the major but also permanent nitrogen removal process thus keeping a high efficiency of microbial conversion is important for stable and efficient nitrogen removal in constructed wetlandsWe would like to sincerely thank Prof Jinbo Zhang and his team for providing valuable advices and help on 15N abundance analysis This study was financially supported by research projects of the Major State Water Pollution Control and Treatment Technique Programs of China No 2012ZX07101006 and No 2013ZX07101014001We confirm that all the data are original and this manuscript has not been published elsewhere and is not under consideration for publication anywhere else All authors have read the manuscript and accept responsibility for this manuscript Its publication has been approved by all authorsWe understand that the corresponding author is the sole contact for the editorial process including editorial manager and direct communications with the office He is responsible for communicating with the other authors about progress submissions of revisions and final approval of proofs We confirm that we have provided a current correct email address which is accessible by the corresponding author and which has been configured to accept an email from zhkuilinjueducn
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